Introduction to Electromagnetic Compatibility

https://www.bmj.com/content/bmj/1/4175/63.6.full.pdf

Methods of Statistics

The dynamic behavior of rigid-block structures resting on a rigid foundation subjected to horizontal harmonic excitation is examined. For slender structures, the nonlinear equation of motion is approximated by a piecewise linear equation. Using this approximation for an initially quiescent structure, safe or no-toppling and unsafe regions are identified in an excitation amplitude versus excitation frequency plane. Furthermore, several possible modes of steady-state response are detected, and analytical procedures are developed for determining the amplitudes of the predominant modes and for performing stability analyses. It is shown that the produced stability diagrams can be beneficial to assessing the toppling potential of a rigid-block structure under a given amplitude-frequency combination of harmonic excitation; in this manner the integration of the equation of motion is circumvented.

Closure of "Rocking of Rigid Blocks Due to Harmonic Shaking"

Reliability is a fundamental requirement in aircraft safety-critical equipments. Its pursuing involves the adoption of protective design concepts such as fault-tolerant or redundant approaches, aiming to minimize mission failure probabilities. Multi-phase motor drives are gaining a growing interest to this extent, because they permit a boost in torque and power density, allowing the design of very compact high efficiency drives with intrinsic fault-tolerant capabilities. This paper presents a five-phase permanent magnet brushless motor drive developed for an aircraft flap actuator application. The motor is designed to satisfy the load specifications with one or two phases open or with a phase short circuited, while a failure in the rotor position sensors is remedied through a sensorless strategy. Design studies aiming to predict the faulty mode performance in case of different remedial strategies are presented. Experimental tests on the drive prototype are included, which confirm its capability to satisfy the planned degraded modes of operation.

High Reliability Permanent Magnet Brushless Motor Drive for Aircraft Application

A back-electromotive force-based sensorless technique for surface-mounted permanent magnet synchronous motor drives is considered in this paper. The model of the observer is developed in the Laplace domain and represents an original approach with respect to state-of-art proposals, normally employing a state-space representation. This allows a more intuitive but equivalent design of the observer's gains, based on the standard frequency response, as compared with eigenvalues analysis. Moreover steady-state errors are obtained from a theoretical point-of-view, including the effects of the most common nonidealities affecting the drive system and parameters sensitivity. Full simulation and experimental characterization of the sensorless drive is provided with reference to a general purpose industrial drive, i.e., both in transient and steady-state and in the most meaningful speed/torque operating conditions.

Design Issues and Estimation Errors Analysis of Back-EMF-Based Position and Speed Observer for SPM Synchronous Motors

This contribution deals with the optimal placement of the decoupling capacitances on the gridded power delivery network of a multichip assembly with interposer. The optimization is performed by means of a nature-inspired algorithm of the genetic class. Different placement strategies are considered and compared. The cost function is based on the evaluation of the input impedance looked into the power and ground rails of the power distribution network and its comparison with a user-defined mask.

Decoupling Capacitors Placement for a Multichip PDN by a Nature-Inspired Algorithm

In this work preliminary yet comprehensive considerations are reported on the possibility for remote monitoring of degraded compression and bolted joints on high voltage overhead power lines. Measurements are performed on new, naturally aged, and artificially degraded joints to quantify the impedance discontinuity introduced along typical HV overhead lines. Numerical simulations, a preliminary time domain reflectometry (TDR) measurement campaign, and circuit simulations are performed on a real power line to study the TDR-based capabilities for the identification of the investigated joint impedances. This study sets the basic concepts to the development of a remote monitoring system for quantifying and locating degraded joints.

Exploring Remote Monitoring of Degraded Compression and Bolted Joints in HV Power Transmission Lines

The aim of this paper is to clarify some important aspects associated with the possibility to detect degraded compression and bolted joints in power transmission lines using a time-domain reflectometry (TDR)-based remote monitoring. The optimization of a TDR-based remote monitoring method is discussed, studying the effects of the source impedance, source-to-line connection, line characteristic impedance, and scope settings, providing useful guidelines for a future method and instrumentation refinement. The experimental results are presented consisting in the inclusion of lumped resistors of several values along a 130-kV power transmission line. The minimum detectable resistance is discussed based on the present available hardware. The TDR-based method is shown to be able to also identify the main features of the line layout such as phase transpositions and different heights of adjacent towers. This paper represents a preliminary base to keep developing the proposed method, with the aim to overcome the actual limitations (costs, reliability, etc.) in power line monitoring.

Detectability of Degraded Joint Discontinuities in HV Power Lines Through TDR-Like Remote Monitoring

This paper deals with the filters based on EBG cavities employed for reducing common-mode currents along differential stripline traces. The crosstalk among differential interconnects routed in close proximity to EBG-based filters, and next to filtered pairs, is accurately quantified. The comparison between the experimental and simulation frequency-domain results validate the proposed filter's effectiveness and make the simulation model reliable for investigating the complex multichannel crosstalk problem. This paper focuses on the stripline environment, where crosstalk occurs among traces routed on adjacent layers, with the EBG cavity acting as a coupling path. Multichannel time-domain simulations complete the characterization of the filter, showing the limited effects of the filter on the intentional differential signal, and the beneficial impact on reducing the potentially radiating common-mode harmonics. The quantification of the common-mode spectrum shows that the filtered harmonics are reduced by 10–15 dB; thus, minimizing the corresponding electromagnetic interference. Design guidelines are defined for the filter layout according to the relative position of unfiltered differential traces, when constraints force them to be placed in close proximity to EBG cavities and filtered pairs. In particular, the best layout for unfiltered traces on adjacent layers is orthogonal with respect to the filtered pair, whereas the parallel routing should be carefully used taking into account the signal bandwidth on the victim pairs.

EBG-Based Common-Mode Stripline Filters: Experimental Investigation on Interlayer Crosstalk

The present paper shows a rotor position estimation technique for a five-phase permanent magnet synchronous motor based on a back-EMF observer, focusing the attention on the design criteria that could be used to construct the sensorless strategy. Due to the polyphase structure of the machine this estimation method deals with a proper linear transformation which allows representing the five-phase motor through an equivalent two-phase model. After a short overview on the back-EMF model for the five-phase motor, the linear transformation and the observer-based estimation technique are presented. The analysis emphasizes on the choice of the observation dynamics through a proper design strategy of the related gain matrix and on some robustness criteria useful to enhance the sensorless strategy. Simulation and experimental results showing the response of the observer during transient and steady-state operation are presented.

Carlo Olivieri

Papers

Decoupling Capacitors Placement for a Multichip PDN by a Nature-Inspired Algorithm

Exploring Remote Monitoring of Degraded Compression and Bolted Joints in HV Power Transmission Lines

Detectability of Degraded Joint Discontinuities in HV Power Lines Through TDR-Like Remote Monitoring

EBG-Based Common-Mode Stripline Filters: Experimental Investigation on Interlayer Crosstalk

Sensorless control of five-phase brushless DC motors